Multiresolution Shape Codes with Applications to Image Retrieval

Arindam Biswas, Partha Bhowmick, Bhargab B. Bhattacharya

Abstract

A novel technique on shape coding of an object in a binary digital image, based on the tight isothetic
polygonal covers of the object in a multiresolution background, is proposed. This technique would be useful
in various analyses and applications related with digital images. To demonstrate the power and usefulness
of such shape codes, we have also proposed an image retrieval scheme based on shape codes. The elegance
of the scheme on shape codes lies in capturing the shape of the object(s) present in an image from its gross
appearance to its finer details by a set of isothetic polygons, in a hierarchicalmanner. The inherent tolerance
present in such a cast of isothetic polygonal shape enables the shape codes of two objects resemble closely
as the grid resolution becomes finer and finer, provided the objects are of similar shapes. The method is very
fast because it does not involve any complex computations, and requires only integer-based comparisons
and additions. Experimental results demonstrate the strength and efficiency of the proposed scheme.